Conventional loading docks typically include an elevated opening in a side of a warehouse or other building. The opening is normally covered by a door, such as an overhead door. To transfer cargo to or from a trailer or other transport vehicle, the doors on the back of the vehicle are opened and the vehicle is backed up to the opening in the building. A vehicle restraint can be employed to hold the vehicle in position in front of the opening. The loading dock door is then raised, and a dock leveler is extended through the opening to provide a ramp from the floor of the building onto the bed of the transport vehicle. Conventional dock levelers typically include a deck that rotates upwardly and away from the floor of the building, and then downwardly as a front lip rotates outwardly. As the deck descends, the lip comes to rest on the bed of the transport vehicle. Once in place, forklifts, workers, etc. can move back and forth over the dock leveler to load and/or unload cargo from the shipping vehicle.
Conventional overhead doors typically include a plurality of rectangular panels pivotally connected together along upper and lower edges. Rollers typically extend outwardly from each side the door panels, and are received in corresponding guide channels on vertical door tracks that extend upwardly along each side of the door opening. Some door tracks extend vertically, or at least generally vertically, above the door opening so that the door is retracted into a generally vertical position when opened. Other overhead door tracks turn horizontally and extend away from the opening so that the door is retracted into a horizontal position above the dock leveler when opened.
It is often desirable to seal and/or insulate warehouses and processing facilities to avoid or at least reduce energy losses. For example, many warehouses are heated during extremely cold weather conditions. If the areas around loading dock doors and dock levelers are not sufficiently sealed and/or insulated, the warehouse can experience significant heat losses. Similarly, refrigerated warehouses can also experience significant energy losses during warm weather conditions if the warehouse is not sufficiently sealed and/or insulated. Although many loading dock openings include exterior seals and/or weather shields to seal between the back end of the shipping trailer and the door opening, these seals do not prevent convective energy losses through gaps around the loading dock doors and/or dock levelers when there is no vehicle present. Moreover, additional energy losses can result from conduction through the door, door track, and dock leveler materials when the door is closed. Accordingly, it would be desirable to reduce energy losses associated with loading dock doors.